Composite spectral measurement method and its spectral detection instrument

ABSTRACT

The present invention discloses a spectral measurement method via continuous light source and discrete light source, and a measurement instrument for non-invasive detection of human body tissue components. Said instrument includes an incident unit, a probe, a receiving unit and a data processing unit. Said composite spectral measurement method improves or strengthens the output light intensity at the wavelength that carries information of the target component within human body. It enables the spectral detection in the whole wavelength range, and thus significantly enhances the SNR of the detecting system. In the non-invasive detection instrument, light from both the continuous light source and discrete light source can be firstly selectively light-split by AOTF, or AOTF conducts light-splitting for the continuous light source, while the discrete light source LD is controlled by a spatial chopper. When data of the spectral curves achieved from said continuous light source and discrete light source are processed, data acquired under different measuring modes can be compared.

This application is a U.S. national filing under 35 U.S.C. 371 andclaims priority from PCT/CN2003/000820, filed 25 Sep. 2003, and from02146704.8-Filed: 4 Nov. 2002 (each incorporated by reference herein).

FIELD OF THE INVENTION

The present invention relates to a detection method and instrument, moreparticularly to a method and instrument for composite spectralmeasurement via a composite light source.

BACKGROUND OF THE INVENTION

Non-invasive detection of the concentration of a certain componentwithin a substance especially human tissue represents great importancein clinical medicine, and in particular, non-invasive detection of theconcentration of blood glucose within human body plays a key role indiabetic diagnosis. Till now some related non-invasive detectioninstruments have been successfully developed by some researchinstitutions in Japan, USA and Western Germany, etc. For most of thesenon-invasive detection instruments, NIR spectroscopy is applied, whereinbecause different components within a substance especially human tissuepossess different light absorption coefficients in NIR range, theconcentration of one or several target components can be detectedthrough analyzing the measured absorption spectra. U.S. Pat. No.5,348,003 is an example introducing a method and instrument usingcontinuous spectra for non-invasive detection of the concentration ofmultiple components in a substance; in U.S. Pat. No. 5,028,787, a methodand instrument for non-invasively detecting blood glucose concentrationthrough analyzing continuous spectra is presented; in JapaneseRegistered Utility Model Applications NO. 2588468, an LED with itswavelength ranging from 1.4 to 1.7 μm is used as a light source fornon-invasive detection; in Japan Patent Publication No. 8-27235, a setupfor chemical analysis is presented using single-wavelength laser. In allthese non-invasive detection methods or instruments, a continuous lightsource or discrete light source is used to create NIR spectra, whereasnone of those instruments produce NIR spectra via a composite lightsource combining continuous light source with discrete light source.

Because generally the absorption wavelength ranges of differentcomponents within a substance especially human body overlap, whendetection is conducted using a discrete light source that emitssingle-wavelength light, only overlapped biological information atcertain wavelength can be obtained, while information at otherwavelengths is very difficult to get. This means, to make a stable andquantitatively non-invasive detecting system, it is a must to achievehigh sensitivity, high precision and good accuracy in a considerablybroad spectral range, and thus measurement can not take place at adiscrete spectrum of a single wavelength or a specific frequency.Firstly, spectra under multiple wavelengths should be obtained. Then bystoichiometric modeling method, the concentration of components ofinterest can be calculated. In this multiple wavelength spectralmeasurement, a continuous light source comprises of, for example, ahalogen lamp and a light-splitting system, or wavelength tunable laser,or several discrete wavelength LDs, or an interference filter. However,there are not so many LDs, and therefore corresponding products do notexit at each wavelength. Furthermore, each filter has a fixedwavelength. To satisfy the requirement for each wavelength, aconsiderable number of filters should be used, making the cost of thewhole system very high. This is why the method using continuous lightsource is often appreciated. Consider that the wavelength range is stilllimited even after the continuous light source passing a light-splittingsystem and that, because multiple target components within the substancedemonstrates strong absorption toward the spectra, e.g., in bloodglucose concentration detection, water has great absorption toward NIRspectra, or because the energy of the spectra of the continuous lightsource is relatively low, the energy of NIR spectra is not enough forthe measurement, and in particular, the spectra of the continuous lightsource may lack some certain NIR spectra that are sensitive to thetarget components. All these factors obviously make useful informationof target components (e.g., blood glucose) that the absorption spectracarry become weaker and directly influence the accuracy, stability andSNR of the detecting system, and thus, it is necessary to introduce oneor several discrete light sources plus the continuous light source toform a composite light source, and by the combination of spectrameasured by different light sources, composite spectra with highaccuracy can be achieved to realize non-invasive detection.

The accuracy of current non-invasive detectors can not meet clinicalapplication requirement, mainly because it is difficult tosimultaneously achieve high energy at both multiple wavelengths and ateach wavelength in the detecting system. However, through utilizingcomposite spectra achieved by a composite light source both multiplewavelengths and high energy can be obtained, so that the SNR of thequantitatively non-invasive detecting system can be enhanced, andnon-invasive detection of the concentration can be realized.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a spectral measurementmethod and instrument via a composite light source, a method andinstrument for detecting the concentration of components that featuresspectral measurement through a composite light source, in particular aninstrument for non-invasively detecting the concentration of certaincomponent, e.g., blood glucose concentration.

Considering that the absorption wavelength ranges of differentcomponents within a substance especially human body overlap intricately,we firstly use a continuous light source that represents continuousspectra in a wide wavelength range for non-invasive detection. In somespecific wavelength ranges of the continuous light source spectra,because multiple target components within the substance demonstratesstrong absorption toward the spectra, e.g., in blood glucoseconcentration detection, water has great absorption toward NIR spectra,or because the energy of the spectra of the continuous light source isrelatively low, the energy of NIR spectra is not enough for themeasurement, and in particular, the spectra of the continuous lightsource may lack some certain NIR spectra that are sensitive to thetarget components. All these factors obviously make useful informationof target components (e.g., blood glucose) that the absorption spectracarry become weaker and directly influence the accuracy, stability andSNR of the detecting system, and thus, within the continuous lightsource spectral range or, otherwise, in a NIR spectral range that issensitive to target components, we introduce one or several discretelight sources as a supplement of the continuous light source.

The present invention is realized by the following aspects.

It is achieved through an incident unit, a probe, a receiving unit and adata processing unit, wherein, the incident unit is composed of thelight source of the present invention; the probe is mainly composed ofthe optical sampling part of the present invention; the receiving unitis mainly composed of the composite spectral method of the presentinvention; the data processing unit mainly performs mathematicalcalculation for the composite spectra achieved by the receiving unit sothat the concentration of a certain target component such as bloodglucose, can be obtained.

The incident unit mainly consists of a light source for creating spectraand an optical setup for light propagation, wherein the composite lightsource is made up of a continuous light source and a discrete lightsource.

It mainly consists of a continuous light source with its light-splittingsystem and at least one discrete light source at a single wavelengthsuch as LD, or at least one narrow-band continuous light source such asLED, or at least one discrete light source at a single wavelength plusat least one narrow-band continuous light source, for instance, LD plusLED.

Presently, instruments for creating continuous NIR spectra generallyinclude Fourier transform NIR spectrometer, raster scanning NIRspectrometer and acoustic optical tunable filter (short as AOTF) NIRspectrometer, etc. A Fourier transform NIR spectrometer cansimultaneously measure signals at all wavelengths with a very high SNRand resolution, and the stability of the system is preferable; however,it is expensive and complicated, and presents a strict requirement forthe usage and the environment, so it is generally used inside a lab. Araster scanning NIR spectrometer can perform scanning within the wholewavelength range, also with a high resolution; besides, the price ismoderate and acceptable, but there is deficiency in the precision,wavelength range, reproducibility and shock resistance. In an AOTF NIRspectrometer, AOTF is used as a light-splitting system. AOTF can performwavelength switch in a very quick way, with good reproducibility andgreat flexibility, but its output spectral energy is relatively low. Inthe present invention, we use AOTF NIR spectrometer as a continuouslight source, and simultaneously, to compensate for the low SNR due toits low output spectral energy, we add a set of discrete light sourcesas complementary light source. Such a structure can enable a setup thatis of good performance, with low cost and unlimited using environment.

In practical measurement, an AOTF NIR spectrometer can be used as thecontinuous light source, while a light source that is able to select andcontrol wavelength can be used as the discrete light source.

Generally, a discrete light source can be a light-emitting diode (LED),a laser diode (LD), or an AOTF, etc. In the present invention one orseveral LDs are used as the discrete light source. LD has goodmonochromaticity and centralized light energy.

Through using spectra from one or several LDs in the non-invasivedetection of certain components within human tissue, accurate biologicalinformation at related wavelength can be obtained

In this spectral measurement method via a composite light sourcecomprising of a continuous light source and a discrete light source,light from the continuous light source and discrete light source can befirst light-split by AOTF selectively, then irradiates on the targetskin after passing corollary equipment such as a fiber. Lightpropagation can also take place in the follow way: AOTF conductslight-splitting for the continuous light source, while the discretelight source LD is controlled by a spatial chopper, and then the lightirradiates on the target skin after passing corollary equipment such asa fiber. Wherein the wavelength range of the continuous light source canbe 0.8˜2.5 μm, while several wavelengths within or beyond the wavelengthrange of the continuous light source can be chosen as the discrete lightsource wavelength. While among the spectra overlapping range of thecontinuous light source and discrete light source, the measurementspectra can be the superposed spectra of the two kinds of spectra; itcan also be only the spectra of discrete light source.

Switching of the composite light source can be conducted through lightpath switching or circuit switching controlled or uncontrolled by AOTF,wherein light path switching can be realized by using electrical signalto control electrical shutter, while circuit switch can be achieved by aspatial chopper or a computer.

In the present invention, optical sampling is achieved by a probe.Regarding the probe in such a non-invasive detection instrument, thecontinuous light source and discrete light source can be designed at thesame position, and according to their light intensity the distributionmode of optical length is decided. They can also be placed in differentpositions, and according to their light intensity the distribution modeof optical length is decided.

In the present invention, the composite spectral method is implementedin the receiving unit. There are two ways for this method, that is,adding the continuous and discrete spectra overlapped or adding thecontinuous and discrete spectra non-overlapped. The first way refers tothat measurement is performed in the overlapping range of these twospectra with these spectra being superposed. The second way means thatin the overlapping range, spectra from only one path are chosen, orspectra from both paths are chosen respectively and measured separately.

For the composite spectral method in the present invention, thesequential control can be achieved in two ways: one is to separatelymeasure the continuous spectra and discrete spectra, that is, firstmeasure the continuous spectra, then the discrete spectra, or thediscrete spectra first while the continuous spectra later; the other oneis cross measurement, that is, the continuous spectra and discretespectra are alternately measured in the order of wavelengths.

In practical use, the composite spectral method in the present inventioncan be exerted in the following four ways. The first one is that boththe continuous light source and discrete light source are light-split bythe AOTF. (FIG. 9 is an embodiment explaining this way.) In everymeasurement cycle, the AOTF starts first, and when the AOTF reaches thewavelength of each discrete light source, a D/A conversion card controlsthe AOTF to begin its special working mode (to change the sampling cycleunder normal working condition into a special sampling cycle), and thenthe combined spectra are superposed and pass the AOTF. At the same time,the computer is notified and then it gives a control signal to selectand start the photoelectric conversion and processing circuits withdifferent gains, and then the AOTF returns to its normal working mode(the recovery of the sampling cycle under normal working condition). Toeliminate thermal noise and make fine tuning more convenient, a shieldedthermal equilibrium cover and fine tuning alignment device 15 are set incorresponding photoelectric conversion and processing circuits, which,in the present invention, can be photoelectric conversion and processingcircuits 13, 14 and 18, whose gains are different from each other.Second, the AOTF conducts light-splitting for the continuous lightsource, whereas the discrete light source directly irradiates on theprobe. (FIG. 10 is an embodiment explaining this way.) In everymeasurement cycle, the AOTF starts first, and when the AOTF reaches thewavelength of each discrete light source, a D/A conversion card controlsthe AOTF to begin its special working mode, and then the combinedspectra are superposed and pass the AOTF. At the same time, the computeris notified and then it gives a control signal to select and start thecorresponding photoelectric conversion and processing circuits 13, 14and 18, and then the AOTF returns to its normal working mode. Third, theAOTF conducts light-splitting for the continuous light source, whereasthe discrete light source directly irradiates on the probe. (FIG. 10 isan embodiment explaining this way.) In every measurement cycle, the AOTFstarts first, and when the AOTF reaches the wavelength of each discretelight source, a D/A conversion card controls the AOTF to let thediscrete spectra among the composite spectra pass, but prevent thecontinuous spectra from passing. At the same time, the computer isnotified and then it gives a control signal to select and start thecorresponding photoelectric conversion and processing circuits 13, 14and 18, and then the AOTF returns to its normal working mode. Fourth,the AOTF conducts light-splitting for the continuous light source,whereas the discrete light source directly irradiates on the probe.(FIG. 11 is an embodiment explaining this way.) In every measurementcycle, the continuous light source controlled by the AOTF works first.When a cycle is completed, a D/A conversion card controls each discretelight source and enables it to begin work, and at the same time, thecomputer is notified and then it gives a control signal to select andstart the corresponding photoelectric conversion and processing circuits13, 14 and 18.

In the present invention, when applying composite spectra with high SNRon multi-variable mathematical processing, to achieve a measuring resultwith high accuracy, we can use principle component regression (short asPCR) method, partial least squares (short as PLS) method and so on fordata processing.

The composite spectral measurement method is achieved via a compositelight source comprising a continuous light source and a discrete lightsource. Such a method improves incident NIR light intensity, and alsoenhances and strengthens the output light intensity at a certainwavelength that carries useful information of the target componentwithin a substance especially human body. It enables the spectraldetection in the whole wavelength range with high accuracy, and thuscomprehensively and significantly enhances the accuracy of the systemfor detecting component concentration.

Said composite spectral measurement method increases spectralmeasurement points that carry information of the target component withinhuman body, and strengthens NIR light intensity at certain wavelengththat carries useful information of the target component in human body.

Said composite spectral measurement method improves or strengthens theoutput light intensity at the wavelength that carries information of thetarget component within human body. It enables the spectral detection inthe whole wavelength range, and thus significantly enhances the SNR ofthe detecting system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing an embodiment of a non-invasive instrument.

FIG. 2 shows a first embodiment of an incident unit in the non-invasivedetection instrument.

FIG. 3 shows a second embodiment of an incident unit in the non-invasivedetection instrument.

FIG. 4 shows a first embodiment of a receiving unit in the non-invasivedetection instrument.

FIG. 5 shows a second embodiment of a receiving unit in the non-invasivedetection instrument.

FIG. 6 shows a first embodiment of a fiber probe in the non-invasivedetection instrument.

FIG. 7 shows a second embodiment of a fiber probe in the non-invasivedetection instrument.

FIG. 8 shows an embodiment of the coupling between a discrete lightsource LD and a fiber.

FIG. 9 (depicted as FIG. 9-1 through FIG. 9-4) is a flow diagramexplaining the data acquisition after the light from continuous lightsource and discrete light source LD is conducted light-splitting by theAOTF and irradiates on the target position.

FIG. 10 (depicted as FIG. 10-1 through FIG. 10-4) is a flow diagramexplaining the data acquisition after the light from continuous lightsource and light from discrete light source LD without light-splittingsimultaneously irradiate on the target position.

FIG. 11 (depicted as FIG. 11-1 through FIG. 11-2) is a flow diagramexplaining the data acquisition after the light from continuous lightsource and light from discrete light source LD without light-splittingseparately irradiate on the target position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

According the composite spectral measurement method mentioned above, wedevelop a non-invasive detection instrument for measuring certaincomponent concentration within human tissue (for example, the bloodglucose concentration). Further detailed description of the presentinvention is given as follows with respect to the following figures andembodiments.

As shown in FIG. 1, the non-invasive detection instrument comprises offour modules, an incident unit 1 a, a probe 1, a receiving unit 1 b anda data processing unit 1 c. Both of the schemes shown in FIG. 2 and FIG.3 is suitable for said incident unit, and said receiving unit can be theone as shown in FIG. 4 or FIG. 5. The incident unit and receiving unitcan be combined in an arbitrary way. Said data processing unit performsmathematical operation on the composite spectra achieved by saidreceiving unit, and thus, the concentration of the target component, forexample, blood glucose, can be obtained.

FIG. 2 shows an embodiment of the incident unit 1 a in the non-invasivedetection instrument. The incident light path of the probe 1 comprisesof an incident fiber 2 of the continuous light source and an incidentfiber 6 of the discrete light source. The continuous light source 5 canbe a tungsten halogen lamp, which is light-split by an AOTF crystal 4.The light path supplementary equipment 3 a of said continuous lightsource includes a temperature control and processing device for thelight source, a focusing lens, a light path channel and a prism, whilethe light path supplementary equipment 3 b of said continuous lightsource includes a polarizing film, a focusing lens and so on. Thediscrete light source 9 can be one or several LDs of differentwavelengths, for example, in blood glucose sensing, five LDsrespectively corresponding to the wavelength 980 nm, 1310 nm, 1550 nm,1610 nm and 1650 nm can be the discrete light source. The LD drivingpower supply 10 is a constant current source. Additionally, a set offocusing lens 8 (FIG. 8 gives an example for explaining a way to realizefiber coupling through a set of focusing lens) are used for coupling anLD with the transmission fiber 6 of the discrete light source, at thesame time, an LD gating baffle 7 controlled by a spatial chopper 7 a ischosen as a gating switch.

FIG. 3 shown another embodiment of the incident unit 1 a in anon-invasive detection instrument. This method is basically similar tothe one shown in FIG. 2, and the difference is in that the discretelight source is selectively light-split as the continuous light sourceis, and it does not use the LD gating baffle 7 controlled by a spatialchopper 7 a as shown in FIG. 2 for light-splitting.

FIG. 4 and FIG. 5 are embodiments of the receiving unit.

FIG. 4 is a graph showing an embodiment of the receiving unit 1 b in thenon-invasive detection instrument. The receiving light path of the probe1 is configured through the connection of a receiving fiber 11 (or 19)and 20 with the photoelectric conversion and processing circuit 13 and14, respectively. Then, the control function of a controller 12 isachieved by a computer's choosing the output signal in correspondingchannels of the photoelectric conversion and processing circuits 13 and14. After being processed by a shielded thermal equilibrium cover and afine tuning alignment device 15, the output signal is transferred to anNI terminal board or shielded joint 16, finally being processed by acomputer 17.

FIG. 5 is a graph showing another embodiment of the receiving unit 1 bin the non-invasive detection instrument. The receiving light path ofthe probe 1 is configured through the direct connection of a receivingfiber 11 (or 19) and 20 with a gain-tunable photoelectric conversion andprocessing circuit 18, and the light path does not go through thecontroller 12. Similar to FIG. 4, after being processed by a shieldedthermal equilibrium cover and a fine tuning alignment device 15, theoutput signal is transferred to an NI terminal board or shielded joint16, finally being processed by a computer 17.

FIG. 6 and FIG. 7 are detailed embodiments of the probe.

FIG. 6 shows an embodiment of the probe 1 in the non-invasive detectioninstrument, where the continuous light source and discrete light sourceare placed at the same position. In the central position of the probe, adiscrete light source transmission fiber 6 and a continuous light sourcetransmission fiber 2 are placed.

A receiving fiber is provided in the external ring of the probe. Such alayout effectively concentrates the incident light intensity, andsimultaneously prevents a majority of stray light that hasn't beenscattered by deep tissue but only reflected by surface from beingreceived.

FIG. 7 is another embodiment of the probe 1 in the non-invasivedetection instrument, where the continuous light source and discretelight source are place at different positions. A discrete light sourcetransmission is provided at the centre of the probe is fiber 6, an innerreceiving fiber 19 is provided in its internal ring, an outer receivingfiber 20 is provided in its external ring, and a continuous light sourcetransmission fiber 2 is provided in the middle ring. Such a layoututilizes the light intensity of the discrete light source thoroughly,where dispersed light irradiates on the target position, and internaland external light paths are used to receive the fully reflected lightfrom the tissue, greatly increasing the intensity of detectablebiological signals.

FIG. 8 shows an embodiment of the coupling between a discrete lightsource LD and a fiber in the incident unit 1 a of a non-invasivedetection instrument. Wherein, a discrete light source LD 9 is coupledwith a discrete light source incident fiber 6 through a focusing lens 8a and another focusing lens 8 b. Such a coupling method can enable theincident light intensity to be received by the fiber as much aspossible.

FIG. 9, FIG. 10 and FIG. 11 show three specific measurement methods.

FIG. 9 shows a processing method of the non-invasive detectioninstrument, a flow diagram explaining the data acquisition after thelight from continuous light source and discrete light source LD islight-split by the AOTF and irradiates on the target position. Both thecontinuous light source and discrete light source have been light-splitby the AOTF. In every measurement cycle, the AOTF starts first, and whenthe AOTF reaches the wavelength of each discrete light source (forexample, the AOTF reaches the first wavelength 980 nm), a D/A conversioncard controls the AOTF to begin its special working mode, that is, toimpose a tunable time delay ΔT1 on the AOTF so that both continuousspectra and discrete spectra are superposed and pass the AOTFsimultaneously. At the same time, a controller 12 is given a signal bythe D/A conversion card to turn on the corresponding photoelectricconversion and processing circuit 13 or 14, and then after the samplingat the wavelength (for example, the first wavelength of 980 nm) of thediscrete light source is completed, the AOTF returns to its normalworking mode and continues sequential acquisition process.

FIG. 10 shows a processing method of the non-invasive detectioninstrument. The AOTF conducts light-splitting for the continuous lightsource, whereas the discrete light source directly irradiates on theprobe. In every measurement cycle, the AOTF starts first, and when theAOTF reaches the wavelength of each discrete light source (for example,the AOTF reaches the first wavelength 980 nm), a D/A conversion cardcontrols the AOTF to begin its special working mode, that is, to imposea tunable time delay ΔT2 on the AOTF; at the same time, the D/Aconversion card outputs a synchronous signal to trigger a spatialchopper 7 a so as to turn on corresponding channel of discrete lightsource (for example, a 980 nm laser), and simultaneously a signal isexported by the D/A conversion card to the controller 12 to turn on thecorresponding photoelectric conversion and processing circuit 13 or 14.After time delay ΔT2, the combined spectra are superposed and pass theAOTF (or only the discrete spectra among the composite spectra passes,while the continuous spectra are prevented), followed by samplingprocess. After the sampling at the wavelength (for example, the firstwavelength of 980 nm) of the discrete light source is completed, the D/Aconversion card imposes a tunable time delay ΔT3 on the AOTF. Then, theD/A conversion card outputs a synchronous signal to trigger the spatialchopper 7 a so as to turn off the corresponding channel of discretelight source (for example, the 980 nm laser). Simultaneously, acontroller 12 is given a signal by the D/A conversion card to turn onthe corresponding photoelectric conversion and processing circuit 13 or14. After time delay ΔT3, the AOTF returns to its normal working modeand continues sequential sampling process.

FIG. 11 shows a processing method of the non-invasive detectioninstrument. The AOTF conducts light-splitting for the continuous lightsource, whereas the discrete light source directly irradiates on theprobe. In every measurement cycle, the continuous light sourcecontrolled by the AOTF starts first. A D/A conversion card outputs asignal to trigger a controller 12 to select and control thephotoelectric conversion and processing circuit 13 or 14. At the end ofone AOTF's working cycle, the D/A conversion card outputs a signal toturn off the AOTF (or imposes a time delay ΔT4 on the AOTF), while atthe same time, the D/A conversion card also outputs a synchronous signalto trigger a spatial chopper 7 a so as to turn on a correspondingchannel of the discrete light source (for example, a 980 nm laser), andthen a signal is exported by the D/A conversion card to the controller12 to select and control the photoelectric conversion and processingcircuit 13 or 14 so as to turn on the corresponding photoelectricconversion and processing circuit 13 or 14 once each discrete lightsource begins to work. After the sampling at the wavelength (forexample, the first wavelength of 980 nm) of the discrete light source iscompleted, the D/A conversion card outputs a synchronous signal totrigger the spatial chopper 7 a so as to turn off the correspondingchannel of the discrete light source (for example, the 980 nm laser) andthen turn on the channel of a discrete light source at next wavelength(for example, a 1310 nm laser). Simultaneously, the controller 12 isgiven a signal by the D/A conversion card to turn on the correspondingphotoelectric conversion and processing circuit 13 or 14. Aftermeasurement of all discrete light sources, the AOTF is resumed (or afterits tunable time delay ΔT4) to begin next working cycle, andsimultaneously the controller 12 is given a signal by the D/A conversioncard to turn on the corresponding photoelectric conversion andprocessing circuit 13 or 14.

1. A composite spectral measurement method comprising: emitting acomposite light from an incident light source composed of a continuouslight source and a discrete light source, the continuous light sourceemitting wideband continuous light, the discrete light source emittingat least one single-wavelength light or at least one narrowbandcontinuous light, wherein the wavelength of the at least onesingle-wavelength light or the spectrum of the narrowband continuouslight is within a range of the spectrum of the wideband continuouslight; using a probe, irradiating the composite light onto a targetposition, and receiving light reflected by the target position at theprobe, wherein the wideband continuous light and the at least onesingle-wavelength light or at least one narrowband continuous light areirradiated onto the target position through an exiting position in theprobe, and the light reflected by the target position is received at areceiving position; in a receiving unit, adding the wideband continuouslight reflected by the target position and the at least onesingle-wavelength light or at least one narrowband continuous lightreflected by the target position in an overlapped or non-overlappedmanner, to obtain a composite spectrum; and in a data processing unit,analyzing the obtained composite spectrum by using a mathematical modelto obtain a concentration of a component of interest.
 2. The compositespectral measurement method according to claim 1, wherein the widebandcontinuous light and the at least one single-wavelength light or atleast one narrowband continuous light are irradiated onto the targetposition respectively through different exiting positions in the probe,and the light reflected by the target position is received at aplurality of receiving positions.
 3. The composite spectral measurementmethod according to claim 1, wherein the continuous light source is anacoustic optical tunable filter NIR spectrometer; and the discrete lightsource is a light emitting diode (LED), or a laser diode (LD), or atunable semiconductor laser.
 4. The composite spectral measurementmethod according to claim 3, wherein the discrete light source iscomposed of one or more laser diodes (LDs).
 5. The composite spectralmeasurement method according to claim 1, wherein the range of thespectrum of the wideband continuous light is any wavelength band within0.8-2.5 μm.
 6. The composite spectral measurement method according toclaim 5, wherein the wavelength of the at least one single-wavelengthlight is one of 980 nm, 1310 nm, 1550 nm, 1610 nm and 1650 nm.
 7. Thecomposite spectral measurement method according to claim 6, wherein thecomponent of interest is blood glucose.
 8. The composite spectralmeasurement method according to claim 1, wherein in the receiving unit,the wideband continuous light reflected by the target position and theat least one single-wavelength light or at least one narrowbandcontinuous light reflected by the target position are measured by asampling sequential control, in which the sampling sequential controlcomprises one of: measuring the wideband continuous light reflected bythe target position first, and then measuring the at least onesingle-wavelength light or at least one narrowband continuous lightreflected by the target position; or measuring the at least onesingle-wavelength light or at least one narrowband continuous lightreflected by the target position first, and then measuring the widebandcontinuous light reflected by the target position; or according to asequence of wavelength, alternatively measuring the wideband continuouslight reflected by the target position and the at least onesingle-wavelength light or at least one narrowband continuous lightreflected by the target position.
 9. A non-invasive composite spectraldetection instrument comprising: an incident light source composed of acontinuous light source and a discrete light source for emitting acomposite light, the continuous light source emitting widebandcontinuous light, the discrete light source emitting at least onesingle-wavelength light or at least one narrowband continuous light,wherein the wavelength of the at least one single-wavelength light orthe spectrum of the narrowband continuous light is within a range of thespectrum of the wideband continuous light; a continuous lighttransmission fiber for transmitting the wideband continuous lightemitted from the continuous light source; a discrete light transmissionfiber for transmitting the at least one single-wavelength light or atleast one narrowband continuous light emitted from the discrete lightsource; a probe for irradiating the composite light onto a targetposition, and for receiving light reflected by the target position; areceiving fiber for transmitting the light reflected by the targetposition and received by the probe; a receiving unit for adding thewideband continuous light reflected by the target position and the atleast one single-wavelength light or at least one narrowband continuouslight reflected by the target position in a overlapped or non-overlappedmanner, to obtain a composite spectrum; and a data processing unit foranalyzing the obtained composite spectrum by using a mathematical modelto obtain a concentration of a component of interest.
 10. Thenon-invasive composite spectral detection instrument according to claim9, wherein a light exiting end of the continuous light transmissionfiber is of a ring shape, a light exiting end of the discrete lighttransmission fiber is of a circle shape, a light incident end of thereceiving fiber is of a ring shape, an end of the probe is of a circleshape, the light exiting end of the continuous light transmission fiber,the light exiting end of the discrete light transmission fiber and thelight incident end of the receiving fiber are concentrically arrangedwith a center at the center of the end of the probe, the light exitingend of the discrete light transmission fiber is located at the center ofthe end of the probe, the light exiting end of the continuous lighttransmission fiber is immediately adjacent to the light exiting end ofthe discrete light transmission fiber, and the light incident end of thereceiving fiber is outside of the light exiting end of the continuouslight transmission fiber.
 11. The non-invasive composite spectraldetection instrument according to claim 9, wherein the receiving fibercomprises an inner receiving fiber and an outer receiving fiber, a lightexiting end of the continuous light transmission fiber is of a ringshape, a light exiting end of the discrete light transmission fiber isof a circle shape, a light incident end of the inner receiving fiber anda light incident end of the outer receiving fiber are both of a ringshape, an end of the probe is of a circle shape, the light exiting endof the continuous light transmission fiber, the light exiting end of thediscrete light transmission fiber, the light incident end of the innerreceiving fiber and the light incident end of the outer receiving fiberare concentrically arranged with a center at the center of the end ofthe probe, the light exiting end of the discrete light transmissionfiber is located at the center of the end of the probe, the lightincident end of the inner receiving fiber is outside of the lightexiting end of the discrete light transmission fiber, the light exitingend of the continuous light transmission fiber is outside of the lightincident end of the inner receiving fiber, and the light incident end ofthe outer receiving fiber is outside of the light exiting end of thecontinuous light transmission fiber.
 12. The non-invasive compositespectral detection instrument according to claim 9, wherein thecontinuous light source is an acoustic optical tunable filter NIRspectrometer; and the discrete light source is a light emitting diode(LED), or a laser diode (LD), or a tunable semiconductor laser.
 13. Thenon-invasive composite spectral detection instrument according to claim12, wherein the discrete light source is composed of one or more laserdiodes (LDs).
 14. The non-invasive composite spectral detectioninstrument according to claim 9, wherein the continuous light sourceemits the wideband continuous light whose spectrum has a range of anywavelength band within 0.8-2.5 μm.
 15. The non-invasive compositespectral detection instrument according to claim 14, wherein thediscrete light source emits the at least one single-wavelength light ata wavelength of one of 980 nm, 1310 nm, 1550 nm, 1610 nm and 1650 nm.16. The non-invasive composite spectral detection instrument accordingto claim 15, wherein the component of interest is blood glucose.
 17. Thenon-invasive composite spectral detection instrument according to claim9, wherein the receiving unit measures the wideband continuous lightreflected by the target position and the at least one single-wavelengthlight or at least one narrowband continuous light reflected by thetarget position using a sequential sampling control, in which thesequential sampling control is adapted to perform one of: measuring thewideband continuous light reflected by the target position first, andthen measuring the at least one single-wavelength light or at least onenarrowband continuous light reflected by the target position; ormeasuring the at least one single-wavelength light or at least onenarrowband continuous light reflected by the target position first, andthen measuring the wideband continuous light reflected by the targetposition; or according to a sequence of wavelength, alternativelymeasuring the wideband continuous light reflected by the target positionand the at least one single-wavelength light or at least one narrowbandcontinuous light reflected by the target position.